1. Field of the Invention
The present invention relates to a session-based broadcasting method that may transmit a message packet from a source node to a plurality of destination nodes out of a radio coverage, in a wireless network including a plurality of sensor nodes and active radio frequency identification (RFID) devices, and more particularly, to an apparatus and method for multi-hop routing decision and looping prevention that may (1) determine a scope of multi-hop routing for receiving a response packet from a destination node within a predetermined session open duration, and (2) prevent a looping phenomenon in which nodes continuously receive and re-transmit message packets, due to a characteristic of a broadcasting communication scheme through which all users may receive message packets.
2. Description of the Related Art
In communication over a wireless network including a plurality of wireless nodes, for example, sensor nodes and active radio frequency identifications (RFIDs), mutual radio frequency interference, and repeated transmission and reception of identical messages, referred to as a looping phenomenon, may occur. In particular, when multi-hop communication is performed by a broadcasting communication scheme, such phenomena may occur more frequently.
In the multi-hop communication performed by the broadcasting communication scheme, various paths from a source node to a distant destination node may exist, and the looping phenomenon in which a transmitted message packet is transmitted and received repeatedly from a receiver to a transmitter may occur frequently.
In a session-based communication system, a session open duration may be predetermined, and communication between nodes may be available only for the session open duration. When the session open duration elapses, packets received after a session is closed may be discarded. Accordingly, a last destination node receiving a message packet, by multi-hop routing, from a first source node transmitting the message packet should send a response within the session open duration. In addition, a transfer of a message packet using multi-hop routing to a destination node incapable of sending a response within the session open duration may be inconsequential.
In addition, everyone may receive a message packet, and broadcast the received message packet again, because all nodes in the wireless network including the source node and the destination nodes may communicate using the broadcasting communication scheme. In this instance, all of the nodes in the wireless network may receive a number of identical message packets.
Accordingly, there is a need for a method that may perform multi-hop routing to a destination node capable of sending a response within a session open duration in a wireless network in which the aforementioned phenomena occur, and prevent repeated reception and transmission of identical message packets.